To conclude this brief series on our new exhaustive review of the putative health benefits of long-term weight-loss maintenance, published in Annual Reviews of Nutrition, here is the summary paragraph of our findings:
“Obesity is well recognized as a risk factor for a wide range of health issues affecting virtually every organ system. There is now considerable evidence that intentional weight loss is associated with clinically relevant benefits for the majority of these health issues. However, the degree of weight loss that must be achieved and sustained to reap these benefits varies widely between comorbidities. Downsides of weight loss that is too rapid and/or extreme may occur, as in the increased risk of gallbladder disease, the presence of excess residual skin, or deterioration in liver histology. Uncertainty also remains about the potential benefit or harm of intentional weight loss on patients presenting with some chronic diseases and on overall mortality. Clearly, well- controlled prospective studies are needed to better understand the natural history of obesity and the impact of weight-management interventions on morbidity, quality of life, and mortality in people living with obesity.”
The is much left to be done and answering some of these questions will become progressively easier as better treatments for obesity become available.
While the health benefits associated with intentional weight loss for some complications of obesity (such as elevated lipids and diabetes) are well documented, high-quality studies to back many other potential health benefits are harder to find.
Just how well (or poorly) the putative health benefits of long-term intentional weight loss are documented for each of the many conditions associated with obesity, is now detailed in a comprehensive review of the literature that we just published in the Annual Reviews of Nutrition.
The 40 page long review, which includes almost 250 relevant publications, supports the following main findings:
- Defining and assessing clinically relevant obesity and weight change are challenging tasks. In a given individual, there is often little relationship between the magnitude of obesity and measures of health.
- Despite its modest effect on long-term weight loss, behavioral modifications thatimprove eating behaviors and increase physical activity constitute a cornerstone for integral and sustainable weight management.
- Intentional weight loss is associated with a clinically relevant reduction in blood pressure, improvement in cardiac function, and reduction in cardiovascular events. The duration and magnitude of weight change required to achieve a significant benefit are still unclear.
- In individuals with impaired glucose metabolism at any stage, intentional weight loss achieved by any means is associated with a proportional reduction in T2DM prevalence, severity, and progression.
- Intentional weight loss is consistently associated with a clinically relevant reduction in triglycerides and increase in HDL cholesterol. The effects of weight loss on LDL cholesterol are less consistent.
- Overall, nonalcoholic fatty liver disease is commonly associated with excess weight and can show marked improvement with behavioral, pharmacological, and/or surgical weight loss. Very rapid weight loss, however, may worsen liver histology in some patients. Simi- larly, gallbladder disease is not only common in patients presenting with obesity but also highly prevalent after intentional weight loss.
- Obesity is widely recognized as a key modifiable risk factor for osteoarthritis, with sig- nificant improvements in pain and function reported with weight loss.
- Obstructive sleep apnea and obesity hypoventilation syndrome tend to improve with moderate weight loss; however, complete resolution is not common and is related to very significant weight loss.
- Asthma and COPD are clearly associated with obesity. Sustained weight loss seems to be associated with a significant improvement in asthma symptoms. Data for COPD are rather limited.
- Pregnant women who under go bariatric surgery seem to be less likely to present obstetric complications such as gestational diabetes, preeclampsia, and macrosomia.
- Data on weight loss and suicide are controversial. Caution may be in order when con- sidering bariatric surgery in patients with a history of suicide ideation or attempt.
- Data suggest that long-term weight loss is associated with an improvement in health- related quality of life. The amount of weight loss required to achieve a significant change, however, remains controversial.
However, there are many other issues where putative benefits of intentional weight loss remain even less clear than with the above.
For many conditions we will likely not know the long-term benefits of obesity treatments till better treatments become available and are tested in affected individuals.
Of all the complications of obesity, diabetes appears to be most sensitive to changes in body weight. Thus, it makes perfect sense for anyone involved in the care of patients living with diabetes to familiarize themselves with the basics of obesity management.
This is probably why I was invited by the Taiwanese Association of Diabetes Educators this weekend to present a plenary talk on the 5As of Obesity Management at their annual meeting, which draws over 3,000 nurses, dietitians, pharmacists and physicians from across Taiwan.
Judging by the interest in the topic, the (surprisingly?) many questions and the number of folks who came up to me after my talk with additional questions – interest in this topic is as big as anywhere else.
Indeed, the importance of obesity in Taiwan may not be readily appreciated by simply looking at the population, who all appear rather slender compared to what we may be used to in Western countries – but remember obesity here is defined as a BMI or just 27 and many obesity related health problems in Asians occur at much lower body weights than in Caucasians.
This week, the New England Journal of Medicine publishes the results of the SCALE Trial, a 56-week randomised controlled trial of liraglutide 3.0 mg vs. placebo (both groups got advice on diet and exercise), on weight loss and other metabolic variables.
The study, that enrolled about 3,700 subjects (70% of who completed the trial), showed greater clinically relevant weight loss in participants treated with liraglutide than with placebo.
Overall, at 56 weeks,
– 2 in 3 individuals on liraglutide achieved a 5% weight loss (compared to 1 in 4 on placebo).
– 1 in 3 individuals on liraglutide achieved a 10% weight loss (compared to 1 in 10 on placebo).
– 1 in 6 individuals on liraglutide achieved a 15% weight loss (compared to fewer than 1 in 20 on placebo).
The adverse effect profile was as expected from a GLP-1 analogue (mainly gastrointestinal and gall bladder related issues).
While liraglutide 3.o mg has now been approved as an anti-obesity agent in the US, Canada and Europe, its key downsides will likely be cost and the fact that it consists of a once-daily injection.
Obviously, as with any obesity treatment, discontinuation will likely result in weight regain (which is not unexpected, given that obesity, once established, becomes a chronic disease).
While in the US, where there are now 4 novel prescription medications for obesity, liraglutide 3.o mg will be the only novel anti-obesity drug available in Canada – a rather sorry state of affairs for those who need medical treatment for this condition.
Where exactly liraglutide will establish itself in the treatment of obesity in clinical practice remains to be seen (time will tell) – but for some patients at least (especially the high-responders), it will hopefully offer a useful adjunct to behavioural treatments.
Disclaimer: I have received honoraria for consulting and speaking from Novo Nordisk, the makers of liraglutide
Today’s guest post comes from Catherine B. Chan and Rhonda C. Bell, Professors in Human Nutrition at the University of Alberta. It describes their Pure Prairie Eating Plan (PPEP) and how they went about developing this rather unique venture into eating local.
Healthy eating is a key factor in preventing and treating chronic diseases such as heart disease, stroke, cancer and diabetes. According to the World Health Organization, good nutrition is one of 4 key factors that could help postpone or avoid 90% of type 2 diabetes and 80% of coronary heart disease.
The Mediterranean Diet has gained popularity as a healthy diet, but evidence gathered through research on Canadian prairiegrown products (canola, flax, barley, pulses, dairy and meats) demonstrates that many local foods have similar nutritional qualities and would be more acceptable and accessible to people who live in Alberta, Saskatchewan and Manitoba.
Our recent project was conceived to develop, test and demonstrate the potential health benefits of a dietary pattern based on foods that are commonly grown and consumed in a “made in Canada” menu plan.
How the Pure Prairie Eating Plan (PPEP) was developed
The original purpose of the menu plan was to help people with type 2 diabetes adhere to the nutrition recommendations of the Canadian Diabetes Association (CDA) by focusing on healthy food choices with a local flavour. The menu plan concept integrates knowledge gained through research related to consumer behavior, behavior change, and nutritional quality of dairy, meats,
canola, pulses and grains.
During its development, it was recognized that a diet healthy for people with diabetes is a diet healthy for everyone. This notion was reinforced in a Consensus Conference with people living with type 2 diabetes, who felt strongly that their diet should not be different from others.
This approach provided knowledge that formed the basis of a 4-week menu plan focused on foods that are grown and readily available in the Canadian prairies. The plan consists of 28 days of diabetes-friendly menus including 3 meals and 3 snacks each day, approximately 100 recipes, tips for healthy eating, pantry and grocery lists and other helpful information.
If followed consistently, the menus meet the recommendations of Eating Well with Canada’s Food Guide on a daily basis, and over 1 week averages approximately 2000 kcal/day with macronutrient distribution consistent with health recommendations.
The menus also provide total fibre between 25 and 50 g/day. Many of the recipes have been obtained from our provincial agricultural commodity groups (see http://pureprairie.ca/oursponsors/).
The recipe ingredients feature many homegrown foods from each food group. They are quick and easy to make…and tasty!
Our Research Findings
Funding was secured through the Alberta Diabetes Institute to pilot test the menu plan concept in a 12-week intervention that measured both quantitative (disease biomarkers) and qualitative (acceptability, accessibility and acceptability) responses to the menu plan of 15 people with type 2 diabetes.
The results, published in the Canadian Journal of Diabetes, showed that most participants liked the menu plan and their A1c decreased by an average of 1%.
However, many were not used to cooking from scratch and cited time as a barrier to using the menu plan more. The benefits of the menu plan included more structure in participants’ diets, increased frequency of snacking, increased awareness of food choices, purchasing healthier foods and better portion control.
Participants were aware of better blood sugar control. Participants were pleased with the variety of food choices and liked the taste of the recipes. They also liked the flexibility of the menu plan.
In the second phase, which included 73 participants, we included a 5-week curriculum delivered in a smallgroup setting with a facilitator and included assessment of hemoglobin A1c as a measure of blood sugar control as well as cardiovascular risk factors. Nutrient intake was assessed using a computerbased 24-hour recall system called WebSpan.
In this study, 86% of those enrolled completed all aspects of the programme, including the 3-month followup. On average, there were decreases in A1c (0.7%), body mass index (0.6 kg/m2) and waist circumference (2 cm). (Note that a decrease in A1c of 0.5% is considered to be a clinically relevant improvement in blood sugar control.)
Although the weight loss was relatively small, it correlated with the reduction in A1c more strongly than any other factor examined.
Analysis of nutrient intakes showed decreases in total energy intake (127 kcal/day), total fat (7 g), total sugar (25 g) and sodium (469 mg).
The Pure Prairie Eating Plan (PPEP)
With promising outcomes regarding the nutritional adequacy and acceptability of the menu plan, and with encouragement from Alberta agricultural commodity groups and others, we packaged and rebranded the menu plan as the Pure Prairie Eating Plan (PPEP): Fresh Food, Practical Menus and a Healthy Lifestyle.
PPEP is available for purchase in selected bookstores throughout the prairies and proceeds from its sale will be used to further research into improving the lifestyle behaviours of Canadians with or at risk of chronic diseases.
For a listing of bookstores currently stocking PPEP, or to buy online, click here
Healthcare providers wishing to purchase 6 copies or more can contact firstname.lastname@example.org for a discount.
We would like to acknowledge the financial support of our sponsors.
Dr. Catherine Chan is Professor of Human Nutrition and Physiology at the University of Alberta. Her research (Physical Activity and Nutrition for Diabetes in Alberta, PANDA) focuses on the development, implementation and evaluation of healthy behavior interventions as well as on identification and testing of healthy food ingredients. She is also the Scientific Director for the
Diabetes, Obesity and Nutrition Strategic Clinical Network of Alberta Health Services.
Dr. Rhonda Bell is Professor of Human Nutrition and leader of the ENRICH project (Promoting Appropriate Maternal Body Weight in Pregnancy and Postpartum through Health Eating) at the University of Alberta. The ENRICH project aims to develop and promote practical strategies for women to maintain healthier weights during and following pregnancy.